A 3D pouch for receiving such a biopharmaceutical product is known, comprising a lower end wall, an upper end wall, and a flexible side wall, which can be in two extreme states—folded flat, and unfolded and deployed—and can be deformed to change from one to the other of these states or may be in any intermediate state. The walls of the pouch, of a plastic material such as polyethylene or a complex comprising polyethylene, define an internal space, which in the folded state is of minimal volume and in the unfolded and deployed state is of maximal volume. This space is intended to receive the biopharmaceutical product for storage, processing, and/or control. Such a flexible pouch, which is biocompatible and disposable, can have a significant volume of at least 50 liters and up to 3,000 liters or more, which justifies calling it “3D”. Such a pouch thus provides a significant capacity while being easy to store. An example of such a pouch is described in international patent application WO00/04131 or in patent FR 2781202. When filled with biopharmaceutical product, such a 3D flexible pouch must be placed in a rigid container which supports it externally. This type of rigid container is suitable for storage, possibly with the possibility of stacking. Some rigid containers are also used for transport, while others are more suitable for weighing operations. The use of a rigid container is therefore very widespread for the handling of fluids contained in a 3D flexible pouch. The storage housing of the container is accessible through an upper transverse opening defined by an upper edge, and is possibly accessible through side doors.
In one implementation, such a rigid container comprises a lower transverse wall and an upright axial peripheral side wall delimiting an upper transverse opening for accessing a housing defined by the inner faces of these walls, suitable for receiving the pouch containing the biopharmaceutical fluid which presses against the inner faces. Patent EP-A-1012073 discloses such a container, further provided with a protective containing wall adapted to be placed transversely in the housing of the rigid container, having dimensions such that the transverse clearance between its free outer peripheral edge and the inner face of the facing side wall of the rigid container is limited.
The flexible pouch is conventionally placed in the storage housing of the rigid container in order to begin loading it. Given the significant weight and the volume of the pouch when filled and inflated, the pouch is initially positioned at least in part on the bottom of the housing formed by the lower transverse wall. This pre-positioning eliminates having to manipulate or transport the pouch when in the filled state. The pouch has an upper end at a distance from the bottom of the housing and typically provided with at least one connection port, and preferably at least two ports, used for filling. The upper end comprises, for example, an inlet port or a port for introducing a biopharmaceutical product and a gas supply port. Corresponding supply lines, each connected to a supply source which is typically external to the rigid container, traverse or extend along the upper transverse access opening, for connection to their respective ports. Alternatively, the filling may be done using a lower supply line. Patent EP-B1-0326730 describes a filling of this type, with the disadvantage that the flexible pouch is more complex, as it is provided with side flaps which limits the usefulness of this type of option. It is generally desirable to limit the complexity and cost of the 3D flexible pouch since it is a single-use disposable item.
It is also known, for pouches of very high capacity (for example 1500 L or 3000 l), to use a hoist system as described in patent US20110271646 to equip the rigid container. The 3D flexible pouch that is used is conventional, but it is necessary to preposition the flexible pouch by lifting it vertically using the hoist system. In this case, the filling with biopharmaceutical fluid is performed from below. The use of a hoist system, which requires attachments to the pouch, is relatively restrictive for an operator.
In practice, the unfolding of the flexible pouch during filling requires human supervision, as incorrect deployment related to pouch flexibility and the mobility of the supply lines can occur. The following have been observed without human intervention:                the flexible pouch catching on the inner faces of the axial wall of the rigid container, resulting in incorrect unfolding and the risk of damage to the disposable flexible pouch,        incorrect orientation of the flexible pouch within the housing of the rigid container, which reduces the capacity of the flexible pouch,        interfering blocking position of the connected lines, which causes the flexible pouch to fill incorrectly, preventing it from reaching a nominal fill volume and resulting in the risk of detachment at the ports of the flexible pouch.        